The rural population of Brazilian Amazonia of mixed African, European, and indigenous ancestry possesses a rich corpus of beliefs and practices concerning the Amazon river dolphin (Inia geoffrensis). Some of these dolphins are believed capable of transforming into human beings at night and causing harm to humans on land. In general, the beliefs about these animals are isomorphic with understandings about human conduct and express preoccupations of these people, as well as explain some episodes of illness. Dolphin narratives encountered in the village which was the focus of this study are more conservative than some in a larger-scale study by Slater (1994).